This invention relates to a film removing device for a rein molded material which can more reliably remove a film formed on the surface of a resin material (matrix resin).
In recent years, there has been an increase in the necessity for recycling a film-coated resin material (a resin molded material coated with a film), which has become useless, from the point of view of environmental protection. To recycle a used resin material having a film of a paint or the like formed on a resin material (matrix resin), i.e., a film-coated resin molded material, it is necessary to process it. During its processing, however, the film penetrates the resin material, markedly lowering the mechanical properties of the resin material. Thus, the film must be removed from the surface of the resin material before processing for recycling.
The following methods have been proposed to remove the film:
(1) Shot blasting method for removing the film by a shot blast. PA0 (2) Filtration method for melting the coated resin through an extruder, and filtering the film through a filter. PA0 (3) Dry roll type rollingmethod for rolling aworkpiece in dry condition by use of a roll pair, and removing the film by utilizing a shearing action resulting from the difference in peripheral velocity between the rolls (disclosed, for example, in Japanese Laid-Open Patent Publication No. 214558/95 and Japanese Laid-Open Patent Publication Nos. 256640/95 to 256643/95).
However, the above-described methods thus far proposed posed the following problems:
Problems with the shot blasting method!
With the shot blasting method, it is difficult to remove the film evenly, if the shape of the molded resin material is complicated. Moreover, if the blast is strongly shot to raise the treating speed, the resin material is burnt to cause quality deterioration, or the blast is embedded in the resin material to make its separation from the resin material difficult.
Problems with the filtration method!
With the filtration method, the film, if thin, deforms and passes through the filter, so that its separation is difficult. An increase in the amount of extrusion for raising the treating speed will impose an excessive compressive load on the resin material, thereby deteriorating the resin material. Furthermore, the need for frequent replacement of the filter arises. Thus, there are limits to the decrease in the treating time and the reduction of the treating cost.
Problems with the dry roll type rolling method!
The dry roll type rolling method is a method for solving the problems of the shot blasting method and the filtration method. According to the dry roll type rolling method, as shown in FIG. 16, a film-coated resin molded material 010 having a film 012 coated on a matrix resin 011 is rolled between a film-side roll 022 having rubber 022a on its peripheral surface and a matrix-side roll 021.
The conventionally proposed dry roll type rolling method, however, has room for improvement in the following respects: When the roll temperature is 30 to 40.degree. C., the film 012, part of the matrix resin 011 and the primer stick remarkably to the film-side roll 022. In the presence of this sticking, the expected film peeling action does not take place. Since the film is minimally separated, continuous operation is difficult. The primer is an undercoat for enhancing the adhesion of the coating.
At a roll temperature above 40.degree. C., the film, part of the matrix resin, and the primer stick to a lower degree. During continuous operation, however, the roll surface temperature rises. As a result, the coefficient of friction between the roll surface and the film, and that between the roll surface and the matrix resin change. Thus, separation of the film becomes difficult, posing difficulty in setting the roll temperature at which operation is possible.